1. Field of the Invention
This invention relates to improved devices for making electrical cross-connections between two sets of conductors and, in particular, to improved devices which increase the amount of electrical isolation between adjacent conductors in the cross-connected sets of conductors.
2. Description of the Prior Art
Wire connecting blocks of the type disclosed in B. C. Ellis, Jr. U.S. Pat. No. 3,611,264, issued Oct. 5, 1971, include an indexing strip and a connecting block, the latter of which carries a plurality of slotted beam contacts. The indexing strip has a plurality of uniform height, spaced-apart teeth along its length. These teeth aid in indexing a first set of conductors. A corresponding plurality of uniform height, spaced-apart teeth carried by the connecting block serve to index a second set of conductors to be cross-connected through the slotted beam contacts to the first set of conductors.
A number of improvements to the basic Ellis, Jr. connecting block are disclosed in B. C. Ellis, Jr. et al U.S. Pat. No. 3,798,587, issued Mar. 19, 1974. In the improved version the spaced-apart teeth in both the indexing strip and the connecting block are staggered in height to facilitate indexing each set of conductors. The Ellis, Jr. et al connecting block is a two-piece structure the parts of which are secured together following insertion of the slotted beam contacts. While this connecting block arrangement has proved to be satisfactory in some applications, we have found that when the connecting block is placed over the indexing strip in cold temperatures certain stresses are applied to the bond between the two connector parts. These stresses often rupture the bond causing failure of the entire unit.
In other applications, such as outdoor environments, moisture collects across the exposed conductor ends. This moisture oftentimes results in short circuits between some of the conductors. In an attempt to alleviate this problem, an insulative, greaselike compound is placed in the connector cavity. While this greaselike compound aids in the reduction of electrical short circuits, unfortunately it further increases the mechanical stresses applied to the joint between the two connector parts as the connector is brought into engagement with the indexing strip. The present application is directed to further improvements in the connecting block structures disclosed in the aforementioned patents.
It is one object of the present invention to alleviate the mechanical stresses produced during engagement of the connecting block with the indexing strip.
Another object is to encase the exposed ends of the conductors thereby electrically insulating them from one another.
A further object of the present invention is to improve the locking arrangement between the connector body and the indexing strip.
Yet another object is to improve the indexing strip in order to facilitate engagement of the connecting block therewith.
Still a further object is to provide a conductor holding arrangement in the indexing strip to hold indexed conductors in place prior to engagement with the connecting block.
An even further object of the present invention is to increase the electrical isolation among a second set of conductors when brought into engagement with the connecting block and ultimately the first set of conductors.
Still a further object is to configure the connecting block such that it is readily engageable with a test cord.